The Dynamics of Peripheral Refraction and Eye Shape in Children with Progressive Myopia Wearing Orthokeratology Lenses

The change of peripheral refraction and the shape of 52 myopic eyes of 26 patients aged 8 to 16 (averagely, 10.4 ± 0,9 years) resulting from overnight wearing of orthokeratology lenses was followed up for 3.2 ± 0.9 years on average. The use of Ortho-k lenses was found to form relative peripheral myopia, whose value correlated with the initial degree of myopia and was averagely equal to -1.4 ± 0.13 D, -1.9 ± 0.17 D and -4.4 ± 0.13 D, respectively for low, moderate and high myopia. The ratio coefficient APA/HD between the length of the anterioposterior axis (APA) and the horizontal diameter (HD) of the eye changed from the initial value, which was averagely equal to 1.01 ± 0.06 (1.00 ± 0.002 for low myopia, 1.01 ± 0.008 for moderate myopia, and 1.02 ± 0.003 for high myopia), to -0.98 ± 0.006 (-0.94 ± 0.001 for low myopia, 0.98 ± 0.007 for moderate myopia, and - 1.00 ± 0.006 for high myopia) by the end of lens wearing term. This dynamics of APA/HD variation is an evidence of eyeball shape change as a result of prolonged use of ortho-k lenses toward the shape of a oblate ellipsoid. This is accompanied by the formation of a peripheral myopic defocus // Russian Ophthalmological Journal, 2016; 1: 62-6.